Process for making an alloying alloy



Jan. 9, 1923. 1,441,479

W. BENNETT. PROCESS FOR M KING AN ALLOYING ALLOY- FILED S PT- 8. I922.

lnveniar Wilsm Ee/z/zett 7 Patented Jan. 9, 1923.

UNITED S ATES PATENT OFFICE.

I WILSON BENNETT, 0F WELLINGTON, NEW ZEALAND.

PROCESS ro'a MAKING An ALLOYING Ame.

I Application filed September 8, 1922. Serial No. 586,998.

To all whom it, may concern);

- Be it known that I, WILSON BENNETT, a

citizen of New Zealand, residin at Wellington, New Zealand, have inventecertain new and useful Improvements in Processes for Making an AlloyingAlloy, of which the following is a specification.

This invention relates to the process of making an alloying alloyreferred to in my application for patent 57 2,100 filed June 30, 1922.

In that a plication I pointed out the advantages 0 making my "alldyingalloy of chromium, etc., directly from theores, thus obviating the stepof previously refining the ores of chromium in making my" alloyingalloy.

An object of the present inventionois to.

produce this alloying alloy in a continuous process and without removingthe.alloying alloy from the furnace in which it is produced.

With this and other objects in view which will appear as the descriptionproceeds, the

invention consists of the novel features hereinafter described indetail, illustrated in'the annexed .drawing and more particularlypointedout in the appended claims.

' angles toFig. 1;,and,

' 40 1 A and B are carbon electrodes and C is a of metal ofapproximately the same compo- Referring to the] drawings wherein thesame letters represent corresponding parts in the different views vFigure 1. is a sectional view of a suitable furnace for use in carryingout my inven-' tion with'the electric circuits and contactsdiagrammatically shown connected to the furnace;

Fig. 2 is a section of the furnace at right Fig. 3 is a sectional viewof a detail of-the water cooled bottom electrode.

water cooled electrode in the bottom of the furnace, said bottom beingpreferably'lined with a magnesite material 0, the test of the body ofthe furnace being the ordinary material. The electrode C, I preferablymake sition as the alloy formed in this furnace.

D, E, F, G, H and J represent switches,

the special functions of which will be later referred to in detail. Theymay be closed or opened to make or break certa'incircuits leading from atransformer 'K to .the electrodes A, B and C. The'electrodes A and 'Bmay be supported by an arm L which in.

turn is supported on a standard P attached meet the requirements of tothe side of the furnace or supported on a base at the side of thefurnace. This standard is screw-threaded at its upper end at Q, and ascrew extended from an upper part M attached to the arm L so that whenthe screw is rotated by a handle R the electrodes A and B will be raisedand lowered in the furnace for a purpose to be described hereafter.

N are digrammatical representations of a water tube passing upwardly andthen horizontally and/downwardly through the bottom of the electrode C,and water passed through the tube N will serve the purpose of keepingcool the electrode during-the operation of the furnace.

I have discovered that certain metals and metalloids when.alloyedtogether exercise a very beneficial effect in minimizing therusting or corrosive properties of iron, when these" metals andmetalloids are present in certain predetermined quantities, for example,I have found that chromium, nickel,

copper, molybdenum, vanadium and silicon,

when added in certain percentages to iron, produce a ferrous alloyhighly impervious to rust and corrosion, in addition to addingexceptional physical properties, such as the ability of withstanding theaction of acids, alkalis and gases to a marked degree.

I have also found that these alloys are suitable to both hot andicoldworking and can be readily manufactured into shapes to ordinarycommercial use.

In order that the iron alloys shall most advantageously possess thequalities herein described, it is necessarythat'the constituent metalsbe substantially free from carbon,

sulphur, manganese and phosphorus, which seriously interfere with theworking properties of the iron alloy, a carbon contentof one pgr centbeing the maximum amount. It

.is even preferable to obtain an iron alloy with a carbon content ofless than one per cent. I Indeed, the total of carbon, sulphur,

' may be added in the form of cupric-nickel metal such as Monel metal.

In carrying out my entire process I take as a base, decarbonized andrefined. iron such as is used for ingot iron or steel manufacture, whichmay be produced in the ordinary manner. in an open hearth furnace, carebeing taken to eliminate carbon, manganese, sulphur and phosphorus tothe lowest possible extent. To the molten iron I add an alloying alloyof chromium, nickel, copper,

molybdenum, vanadium and silicon in such percentages to produce thequantity and quality of the completed iron alloy desired, usingaluminium as a. deoxidizing, degasifying andsolidifying agent.

My method of preparing the alloying alloys is of prime importance and Iprefer to use the furnace illustrated in the drawing in making thisalloyingalloy.

To produce the alloying alloy -I first intimaitely mix crushed chromiteore wit-h coke and pile this charge of material around the electrodes A.and B.. This charge is then covered with a. slaggingmaterial of limeand fluorspar. The furnace is then set into operation as an arc furnaceby closing the switches E and either G, H or J, depending upon theamount of current that. I wish passed through theelectrodes AB. theswitches D and F being left open. This will produce an are from thelower extremities of the electrodes A and B. The charge is completelymelted and the result is a fused mass of chromlum, iron, carbon andmetalloids. This product is known commercially as ferro chromium. Inthls stage of the process the molten bath of metal will be in the metalminimizes the chromium oxide losses in theslag to a marked degree whichotherwise are relatively high when silicon is switches carbon contentrequired is obtained.

not employed during the decarburizing process.

The electrodes A and B are now depressed so as to barely clear the metalsurface, allowing only a small gap between the molten metal and theelectrodes to prevent the metal bath from being impregnated by carbon Ifrom the electrodes. The furnace is now operated as a. resistance orincandescent furnace with the upper electrodes A and B connected inparallel to one pole and the water cooled metal electrode C situated inthe base of the hearth, connected to the opposite pole. This ma beaccomplished by closing F and either G H or J, depending on the amountof current. desired, and opening switch E. The temperature is raised andthe decarburizing process proceeded with until a test piece shows therequired carbon content of the finished alloying allo The additionalalloys of nickel, copper, molybdenum and vanadium should be introducedat this stage. They may be added in the form of metals or ferro alloysof these metals, previously prepared. The chromium and iron contents ofthe metal bath should be determineduand. chromite ore or ferro chromiumshould be introduced if the chro- "mium content should be found to betoolow,

excess of the desired amount. The decarburizing process is proceededwith until tile.

11 practice: it will be found'that the components of the alloyingmaterials are easily oxidized, especially'the silicon and chromium-These oxidized products form a-chromiferous'silicate slag. This slag canbe employed to great advantage as fluxing material for subsequentmeltings/and decarburization.

The slag is carefully removed, leaving the metal bath with a cleansurface. A covering of crushed lime is then thrown on the metal bath andthe temperature of the furnace is raised .to a. point whichwill-reducethe lime very quickly to a fluid state. When the lime slack is melted,coke dust is carefully thrown on top of the slag around and between theelectrodes A, B, care being taken not to allow coke to come in contactwith the molten metal. The upper electrodes A, B, are elevated and thefurnace operated as an arc furnace at high temperature to form a calciumcarbide covering of the lime and coke. Immediately the coke dust isthoroughly incorporated with the lime, the upper electrodes are loweredto slightly above the metal bath surface as before described by turningthe. handle R and operating the screw to lower the electrodes, and thefurnace is then operated as a resistance or incandescent furnace,setting up a flow of metal under the calcium carbide flux. This is thethird stage of the process and will be found in practice to speedilyeliminate sulphur, phosphorus, manganese and silicon to an extremelylowdegree. The completed alloying alloy is then run into the ladle andthe refined iron previously referred to as ob tained from the openhearth furnace is poured directly into the mixture. 4 It is verydesirable in order toobtain satisfactory results that the completed ironalloy be made with accuracy, and to insure" that the resulting compoundshall contain the proper proportions as specified. T0 attain this resulta ladle with a suitable Weighing attachment is advisable and the desiredpercentage, by weight, of the alloying alloy run into the ladle from theelectric furnace Into this molten mixture sufficient of the refined ironfrom the open heart-h furnace is poured to produce the quantity andquality of the completed iron alloy desired. Aluminium or'siliconeither, or both, being inserted into the ladle toact as a deoxidizing,

I degasifying and solidifying agent during I is then run into ingots orsuitable moulds to,

the mixing stage. The completed iron alloy produce castings, transferredto soaking pits, rolled, pickled, annealed and manufactur ed into sheetsand shapes in the usual manner.

It is evident-that my invention permits of various modification, forexample, the proportion of copper, nickel, molybdenum, vanadium orsilicon may be changed considerably, and under certain conditions one ormore of theseelements may be omitted, al-

though I prefer to use them approximately in the-percentages specified,Y i

I claim as my invention 1. The process of producing an alloying alloywhich consists in mixing clironium ores Wath ore reducing agents in anelectric I furnace, passing an electric are through the mixtureto reduceand refine the metals, removing the resulting slag, adding a decalburzmg mixture including a high content of-sihcon to the remaining metalsand passmg a current through the mass to reduce the Y slag.

silicon.

carbon to a low percentage and to eliminate excessive chromide oxidelosses during the decarbonization, and removing the resulting 2. Aprocess of producing an alloying alloy from ores, which consists inmixing chromite ores with a carbonaceous material, covering the samewith a basic material, then passing an are through the ores to melt andreduce the same, removing the same with a slagging material and passingan electric aretherethrough, removing the slag thus formed, coveringthetop of the metal with lime, a chromium ore, mill scale and silicon,passing a current through the mixture to rid the alloy of its carboncontent as described; 7

6. The process set forth in claim 5, together with the step of addingsome form of'nickel and copper to the resulting alloy.

7. The process-set forth in claim 5 togethe r with the, step of addingnickel, copper, molybdenum and vanadium to the alloy formed. 3 r, p

In testimonv whereof I afiix my signature in presence of two witnesses.

Witnesses:

CHAS. B; COMPTON, 'Srnwan'r L'. WHITMAN.

. loy as set forth in claim 1 and adding to the WILsoN BENNETT.

